This invention relates to improvements in an inspection station apparatus integrated into an integrated circuit (IC) chip manufacturing assembly line. Following a visual inspection of an IC chip, and prior to encapsulation, a machine operator causes the apparatus of the present invention to punch one die frame lead of an IC die as an indication of a defective die which requires subsequent removal (and/or recycling).
A die is an integrated circuit chip composed of silicon, silicon oxides, conducting surfaces, and insulating surfaces bonded to a lead frame and later encapsulated. The punch is activated by an inspector inspecting each IC die as it is indexed forward on its die frame through the inspection machine. The visual inspection of the IC die follows a wire bond procedure which includes the thermocompression bonding of one end of a gold or aluminum lead wire to an aluminum bonding pad on the die, with the other end of the wire being bonded to a lead frame lead. If any defect in the product is noted either in the bond or otherwise, the inspector initiates the punch operation of the present invention and a small section of a lead is removed. As set forth below, only a single lead in each defective IC die is punched. During subsequent processing of the IC die, and generally after encapsulation, an optical sensor scans the package leads for defects. If a missing section of lead wire is noted, the IC package automatically is removed from the assembly line.
The apparatus of the present invention comprises a universal punch block apparatus, and can accommodate the following types of IC devices: single in-line package (SIP), single in-line memory module (SIMM), small outline J leaded (SOJ), plastic leaded chip carriers (PLCC), dual in-line package (DIP) and zig-zag in-line package (ZIP). Commercially available punch block apparatus used by Applicant functioned adequately for their intended purpose, but were characterized by a number of problems, namely:
1. The punches were generally not adaptable to more than one product line, due to lack of adjustment features;
2. The top of a die insert was fixed, creating an interference with certain IC die products;
3. Imprecise punch positioning and uneven operation resulted from the many separate parts comprising the apparatus;
4. A change in product line inspected by such apparatus' often required changing the entire punch block assembly and required siqnificant adjustments to location of die frame indexing devices; and
5. The punch was fixed in relation to the die leads, i.e. only one specific die lead could be punched.
The apparatus of the present invention solves each of these problems with a unique design by a simple exchange of punches, adjustable punch holding devices, moveable die inserts and a rigid single piece base for the apparatus.